Fix gdb.base/advance-until-multiple-locations.exp with some compilers

Fix gdb.base/advance-until-multiple-locations.exp with some compilers

The tests in gdb.base/advance-until-multiple-locations.exp that expect
the program to stop at a caller fail on some systems, depending on
compiler.  E.g., with Clang 10, I see:

 advance ovld_func
 0x00000000004011a3 in test () at /home/pedro/gdb/binutils-gdb/src/gdb/testsuite/gdb.base/advance-until-multiple-locations.cc:51
 51        ovld_func ();
 (gdb) FAIL: gdb.base/advance-until-multiple-locations.exp: advance_overload: second advance stops at caller

And Tom de Vries saw:

 ...
 (gdb) until ovld_func^M
 main () at advance-until-multiple-locations.cc:61^M
 61      }^M
 (gdb) FAIL: gdb.base/advance-until-multiple-locations.exp:until_overload: until ovld_func
 ...

Which exact line the program stops is not important.  All we care
about here is that the program stopped at the caller function.

So fix it by adjusting the patterns to match the frame header/function
reported by the breakpoint hits instead of the source lines text.

Tested against:

 - gcc {4.8, 4.9, 7.3.1, 9.3.0, trunk-20200828}
 - clang {5.0.2, 10}

gdb/testsuite/ChangeLog:

	* gdb.base/advance-until-multiple-locations.exp
	(advance_overload, until_overload): Adjust to match the
	frame/function header instead of the source line text.